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Power output of tube amps compared to solid states

I'm having a hard time trying to figure out how tube amp power output relates to solid state power output. I've been looking at the classifieds for tube amps and I see lots of tube amps with 50w or 60w output, but nothing close to the 250w output typical of solid state amps.

So I have no idea what type of tube amp is required for my set up, right now I'm using totem forests with a required power rating of 150w-200w at 8ohms. The bass is so powerful on these that I have the sub crossover set to 40hz.

My question is, are tube amps so efficient that 50w from a tube sounds like 150w from a solid state? Or will 50w output from a tube severely limit how loud I can play my speakers? If so, are tubes usually meant to be driving super-high efficiency speakers?

I had previously tried a tube pre-amp with a solid state power amp (both musical fidelity) and didn't like the results because the imaging suffered greatly, even though the music sounded nicer from a distance. Now I want to try a solid state pre-amp (bryston) with a tube power amp (no idea which brand to look at), but I don't know how much power output I need or if it will even be possible with my speakers. Does anyone know what I would require?
acrossley
shadorne's avatar
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shadorne
7,477 posts
 
For instance, my Merlins are said to have critically damped (whatever that means)

Critically damped means a Q of 0.707. It is a function of the driver Qes (electrical Q) and Qms (Mechanical Q) and the acoustic damping from the box (air pressure).

A design that is overall critically damped is the fastest design that returns to the rest or "zero" position without overshooting the rest position when the power is removed.
unsound
7,334 posts
 
Shadorne, well done.
The link Atamasphere provided is really worth a look.
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atmasphere
11,962 posts
 
Koegz, I read that paper some years back, but I have not seen it on the web. Do you know of a link to it?
koegz
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I do not.
shadorne's avatar
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shadorne
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04-10-10: Unsound
Shadorne, well done.
The link Atamasphere provided is really worth a look.

Thanks - yes it was very interesting and useful. Please bear in mind that all the experimental results were for "infinite baffles" (no box).

The acoustic suspension is usually the most powerful damping force in a box speaker (until you get below the port resonance in a ported design when it begins to behave like an infinite baffle). This controls whether the speaker will sound "boomy" (underdamped) or "tight" (critically damped) over the designs resonant frequency. In practice it is rare to find a design that is overdamped.

In infinite baffles the amplifier damping along with Qes becomes the dominant factor...and in this case the match with the amplifier is indeed critical as the amp can control the overall system Q to a large degree - to the good or the detriment of the sound.
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